Adaptive Backstepping Based Fault-tolerant Control for High-speed Trains with Actuator Faults

In this paper, the fault-tolerant control problem is addressed for high-speed trains with unknown time-varying system parameters, traction system actuator faults and disturbances. To represent the unknown time-varying system parameters in mathematical form, a new piecewise time-varying indicator including commonly used 0-1 case, is employed, which results in a piecewise time-varying nonlinear model with some unknown parameters and piecewise disturbances. For the healthy system with the time-varying indicator in the unknown forms and having known switching time instants, an adaptive backstepping controller is proposed to deal with the unknown system parameters and disturbances and achieve the position tracking. Further, the adaptive backstepping based fault-tolerant controller with adaptive laws is developed to guarantee the system states boundedness and the position tracking, in the presence of unknown actuator faults. Based on Lyapunov function, the stability of the closed-loop system is proved. Simulation studies on CRH2 (China Railway High-speed Train II) verify the performance of the proposed fault-tolerant control scheme.